Thousands of vaccines are being delivered to health centres in New Zealand's Canterbury district as a measles outbreak has widened to 20 confirmed cases, with health officials warning the number is expected to rise over the coming days and weeks.
Measles cases are rising globally, including in wealthy nations such as the United States and Germany, where some parents shun the vaccines mostly for philosophical or religious reasons, or concerns, debunked by medical science, that the vaccines against measles, mumps and rubella (MMR) could cause autism.
With Canterbury health centres running out of vaccines since the start of the outbreak in late February, 3,000 MMR vaccines have been brought by Sunday, and 18,000 more are to be delivered to the region by Wednesday.
"It can now be assumed that measles is circulating widely in our community," the Canterbury district health board said in a statement.
The latest outbreak came from people who were thought not fully immunised. People are considered immune if they have received two doses of the MMR vaccine, have had a measles illness previously, or were born before 1969.
"Unimmunised people who come within two metres (6.56ft) of an infectious person, however briefly, have a 90 percent chance of contracting measles," the Board said.
Even though the vaccine is highly effective, globally around 110,000 people died from measles in 2017, according to the World Health Organisation (WHO). Most of them were children under the age of five.
New Zealand's Health Ministry said in a statement in late February that since 2012 all cases of measles in New Zealand came from travellers bringing the disease from overseas.